If you check out FlightRadar, chances are an airplane is flying close to you. You might even be less than a ten-kilometer radius from an airport. In these cases, a simple SDR receiver paired with an antenna can let you tap into all those communications 🥷🏽.

Air traffic communications use amplitude modulation even though most radio communications today use frequency modulation.
While FM generally delivers better signal quality, it's more complex and requires hardware that’s more power-hungry and heavier, a real concern in aviation 🛩️.
Plus, AM is way more robust than FM, meaning the signal holds up better against obstacles like bad weather, mountains, and large buildings. This lets the transmission reach farther distances.

Air traffic communications use vertical polarization. This refers to the direction of the electric field in an electromagnetic wave. This site explains the various types of polarization nicely.
Simply put, a vertically polarized wave should be picked up by an antenna oriented vertically. Otherwise, you risk losing a large portion of the signal.

Have you ever seen the frequency allocation spectrum from the ANFR?

It can be hard to tell on a small screen, but zoom in on the region allocated to aeronautical communications within the VHF band.

These frequencies fall between 108 and 137MHz. Now you need to know which frequencies within that range are used near you so you can tune in.

A great site that shows the frequencies used in aviation, complete with a map, is Openaip. You can view the map by clicking here.
For example, let’s look at Bordeaux-Mérignac BOD airport.

On the side, you can see a bunch of frequencies used by the airport, including the control tower (labeled TWR).

In my case, I use SDR++ because I like the software, but any SDR software works similarly.

Here’s a snippet of what I managed to pick up:

Communications aren’t continuous, so be patient. Wait until you see a peak, tune in, and enjoy the listen.
Also note that you can use a squelch setting to mute background noise and listen only when a transmission occurs.